MESOSCALE DISCUSSION 0089
   NWS STORM PREDICTION CENTER NORMAN OK
   0613 PM CST TUE FEB 10 2009
   
   AREAS AFFECTED...NW TX THROUGH CNTRL AND ERN OK
   
   CONCERNING...TORNADO WATCH 8...9...
   
   VALID 110013Z - 110145Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 8...9...CONTINUES.
   
   THREAT FOR MAINLY DAMAGING WIND APPEARS TO BE INCREASING WITH
   EVOLVING SQUALL LINE ACROSS CNTRL OK. HOWEVER...ISOLATED TORNADOES
   AND LARGE HAIL REMAIN POSSIBLE WITH EMBEDDED SUPERCELL STRUCTURES.
   MORE DISCRETE STORMS FROM NW TX INTO ERN OK HAVE BEEN SLOW TO
   INCREASE...BUT THREAT FOR A FEW TORNADOES WILL REMAIN POSSIBLE WITH
   THIS ACTIVITY NEXT SEVERAL HOURS.
   
   TREND HAS BEEN FOR STORMS THAT INITIATED ALONG THE DRYLINE OVER
   CNTRL OK TO GROW UPSCALE INTO A QUASI-LINEAR MCS. ORGANIZED STORM
   STRUCTURES ARE EVIDENT WITHIN THE LINE INCLUDING SUPERCELLS ON THE
   NRN END AND A BOW ECHO MOVING RAPIDLY NE THROUGH CNTRL OK NEAR
   NORMAN. A COLD FRONT CURRENTLY FROM WRN OK SSWWD THROUGH WRN TX WILL
   SURGE RAPIDLY EWD OVERNIGHT AND OVERTAKE DRYLINE AS SHORTWAVE TROUGH
   EJECTS THROUGH OK AND TX. DEEP LAYER LIFT ASSOCIATED WITH EJECTING
   UPPER JET AND INCREASING LINEAR FORCING SHOULD HELP SUSTAIN THE
   QLCS. THROUGH THE PRIMARY THREAT MAY TRANSITION TO DAMAGING WIND AND
   HAIL ALONG THE LINE...ISOLATED TORNADOES WILL REMAIN POSSIBLE WITH
   ANY EMBEDDED SUPERCELLS.
   
   FARTHER EAST IN WARM SECTOR...STORMS HAVE BEEN SLOWER TO INCREASE
   MOST LIKELY DUE TO WEAKER MID LEVEL LAPSE RATES ASSOCIATED WITH A
   THERMAL RIDGE DOWNSTREAM FROM UPPER TROUGH. HOWEVER...LEADING EDGE
   OF MID LEVEL COOLING SHOULD BEGIN TO OVERTAKE THIS REGION LATER THIS
   EVENING. THIS ALONG WITH STRENGTHENING LOW LEVEL JET WITHIN
   APPROACHING UPPER JET EXIT REGION SUGGEST THE MORE DISCRETE WARM
   SECTOR STORMS SHOULD INTENSIFY THIS EVENING WITH A THREAT OF
   SUPERCELLS CAPABLE OF PRODUCING TORNADOES AND LARGE HAIL.
   
   ..DIAL.. 02/11/2009
   
   
   ATTN...WFO...SGF...TSA...FWD...OUN...SJT...
   
   LAT...LON   32039932 34979788 36739641 36869474 36059405 34829452
               33349731 32039932